Bore-opening apparatus



May 27, 1930.- L E.'CROFT BORE OPENING APPARATUS Filed Oc't. 26, 1928 3' Sheets-Sheet '1 61M wag May 27, 1930. L. E. CROFT BORE OPENING APPARATUS Filed Oct. 26; 1928 3 Sheets-Sheet 2 I aHknMq May 27, '1930. E. d'RbFT BORE OPENING APPARATUS Filed Oct. 26, 1928 3 Sheets-Sheet 3 glwoen roz Patented May 27, 1930 UNITED STATES ATENT OFF-ICE LORENZO E. CROFT, F DENVERQCOLOBADO, ASfiIGNOR '20 GARDNER-DENVER COIYI- PANY, 01 DENVER, COLORADO, A CORPORATION OF DELAWARE BORE-OPENING APPARATUS Application filed. October 26, 1928. Serial No. 315,325.

The present invention relates to machines for opening the bores of drill steels and the like, the object being to provide novel and simple apparatus which can be cheaply produced and is highly eifective. In the accompanying drawings:

Figure 1 is a plan view of the preferred form of the structure.

Figure 2 is a longitudinal sectional view on the line 22 of Figure 1.

Figure 3 is a longitudinal sectional view on an enlarged scale, showing the path of the fluid when the tool is in operation and the piston is at the front end of its stroke. Figure 4; is a similar view, but showing the piston at the rear end of its stroke.

Figure 5 is a rear elevation of the rear head. Figure 6 is a longitudinal sectional view therethrough and showing the means for securing the said head to the barrel.

Figure 7 is a front elevation of the head. Figure 8 is a sectional View on the line 8-8 of Figure 2.

In the structure shown, the tool includes a barrel 9 containing a piston chamber 10 and having a reduced externally threaded front end 11 On said front end is screwed a housing 12 that contains a tappet. This tappet is in the form of a spool-shaped body 13 having a head 14 projecting from the front end of the housing and provided with a socket 15 that detachably receives a bore opening pin 16. This pin is held in place by a suitable key 17. The rear end of the body is formed with a rearwardly extending shank 18. A

reciprocatory piston hammer 19 operating in the piston chamber 10 has a reduced front end 20 adapted to strike the shank 18, and the .tappet thus delivers the kinetic energy of the blow to the bore-opening pin 16..

It will be noted that the tappet constitutes a permanent part of the tool, and that the pin can be interchanged as desirable. Moreover the pin is not directly struck by the piston hammer.

The rear end of the barrel 9 is externally threaded as shown at 21, and has screwed thereon a rear head 22, which is provided with a depending offset port-ion 23 that projects below the barrel. The ofiset terminates in a nipple 24 to which may be coupled a motive fluid supply hose. The bore of the nipple opens into a valve chamber 25, from which leads a passageway 26 formed in the extension 23 and rear head 22 and opening into a distributing valve chamber 27. Surrounding the passageway 26 at the rear side of the valve chamber 25 isa valve seat 28, with which cooperates a valve 29 having a stem 30 that projects through the rear side of the offset L extension 23. This valve 1s made accessible by means of a detachable plug 31 threaded into the front end of the extension in line with the valve. Interposed between the plug and valve is a spring 32 that serves to normally hold the valve in closed position.

The tool is movably supported by a bracket 33 having an offset flat portion 34 adapted to be placed against a suitable mounting and held there by cap screws or bolts passing through openings 35. The front end of this bracket has an ofisetarrn 36 terminating in a collar 37 that slidably receives the rear portion of the housing 12 of the tool. The rear head 22 has outstanding cars 38, through which are passed bolts 39 slidably mounted in an offset arm 10 formed on the rear end of the bracket 33 and extending behind the rear head 22. Coiledsprings ll are located on the bolts 39 and are interposed between housing 12 and thereafter the entire tool will be moved rearwardly with respect to the supporting bracket 33. This will cause the stem 30 of the valve 29 to contact with the extension 12 of the arm 10 and said valve will be stopped. The continued rearward movement of the tool will cause the opening of the valve 29 so that fluid supplied to the nipple 24 willpass through the passageway 26 to the tool, as indicated in'Figure 4.

An automatic valve is provided for distributing the motive fluid to reciprocate the piston. To this end a tubular bushing 43 is mounted in the rear head and is in open communication with the passageway 26. Fitted into the rear end of the barrel is a valve casing 44 in which is a reciprocatory distributing valve 45 slidably mounted on the bushing 43 and has an outstanding flange 46 on its rear end. The valve casing 44 is provided in its front end with annular grooves 47 and 48 adapted when the valve 45 is at the front end of its stroke, to be in communication through the medium of an annular groove 49 formed on the exterior of said valve. The groove 47 is in constant communication with the interior of the Valve 45 by ports 50. Leading from the groove 48 is a plurality of passageways 51 that open into the front end of the piston chamber 10. The open front end 52 of the valve casing 44 is adapted to be in communication with the groove 47 of said valve casing when the valve is in its rear position, as shown in Figure 4, and, this constitutes a passageway for the motive iii? to the rear end of the piston chamber 16.

It will be evident therefore that when the valve 45 is at the front end of its stroke, the piston will be in a similar position, as shown in Figure 3. Motive fluid therefore that is permitted to pass to the distributing valve 45 by the opening of the valve 29, will pass through said valve 45 and by way of the ports 50, grooves 47, 49 and 48 and passageways 51, to the front end of the piston chamber, thereby driving the piston rearwardly. This is shown in Figure 3. When the piston V is at the rear end of its stroke, the distributing valve 45 will be at the rear end of its stroke. Consequently motive fluid will pass through the ports 50, groove 47 and opening 52, into the rearv end of the piston chamber 10 and drive the piston forwardly.

The barrel 9 and rear head 22 are held against accidental relative rotation by means of a pin 53 engaging an annular rib 54 on said barrel and engaging the front end of the rear head 22. As show in Figures 58 inclusive the front end of the rear head is provided with a plurality of sockets 55 and the rib 54 is provided with a series of openings 56 therethrough as illustrated in Figure 8. The openings in the rib are not the same distance apart as the sockets 55, but certain of the openings and sockets can be alined to permit the introduction of the holding pin 53. This arrangement permits of a fine adjustmerit of the head and barrel and their being secured when the desired adjustment is obtained. The pin 53 is held against detachment by a spring ring 56 surrounding the barrel and located in the path of the pin as illustrated in Figure 6. 1

From the foregoing, it is thought that the construction, operation and many advantages of the herein described invention will be apparent to those skilled in the art without fur ther description and it will be understood that various changes in the size, shape, proportion and minor details of construction may be resorted to without departing from the spirit or sacrificing any of the advantages of the invention.

What I claim, is

1. In apparatus of the character described, the combination with a fluid operated tool comprising a barrel having a piston chamber, of a hammer piston in the piston chamber, a bore opening pin operated on by the piston and projecting beyond one end of the hammer, a support for the tool and on which it movably mounted, including a portion located in rear of the tool, a rear head for thebarrel having an ofiset portion, said oil'- set portion having a motive fluid supply passageway, means for distributing the motive fluid from the passageway to the tool, a valve in the offset portion and out of line with the piston chamber controlling the supply passageway and having a stem projecting from its rear end and in a position to be engaged by the said portion of the support to open the valve when the tool is pushed rearwardly by an article forced upon the bore opening pin.

2. In apparatus of the character described, the combination with a fluid operated tool comprising a barrel, of a hammer piston therein, a bore opening pin operated on by the piston and projecting beyond one end. of the hammer, a bracket on which the tool is slidably mounted and including an offset arm in rear of said tool, a rear head for the barrel having an offset stem portion provided with an internal valve chamber and a passageway for the supply of motive fluid leading through the chamber to the tool, a valve in said chamber controlling the passageway and having a stem projecting through the rear side of the offset portion, and in position to engage the arm, a removable plug in the front side of the offset portion giving access to the valve, and a spring interposed between the tool and arm for urging said tool forwardly to permit the valve to remain closed,

In testimony whereof, I affix my signature.

LORENZO E. CROFT. 

